Water Tank + Pink Batts

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Shindig

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# 213985 22-Apr-2017 11:21

The nights and morning are getting colder, I noticed this morning the shower took longer to flow hot water.

The water tank in the garage isn't insulated.

Question is (refer to pic), can I buy a roll or two of pink batts, and insulate the water tank? The tank its self is stored in an top accessible wooden frame to hide it out the way. If I was to fill the area with pink batts would that be OK?

Thinking from a fire risk\hazard

Is there other material on the market that would work better?

cheers

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# 1768796 22-Apr-2017 11:37

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there are actual products designed specifically for the purpose

https://www.mitre10.co.nz/shop/search?q=Hot-Water-Cylinder-Wrap&categorySelected=Entire+site

https://www.bunnings.co.nz/greenstuf-insulation-eco-wrap-hot-water-cylinder-wrap_p00264711

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Jase2985

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# 1768797 22-Apr-2017 11:38

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how is the tank heated?, how warm is the tank to touch?

the time it takes for the shower to get warm will be due to the length of pipe and the need to heat it more so than the tank being uninsulated. as the tank should always be the correct temperature (unless you have just used a lot of water, then it will be reheating that)

Morgenmuffel

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# 1768798 22-Apr-2017 11:39

better pic of what it actually looks like

http://www.sustaintrust.org.nz/shop/smart-homes/cylinder-wrap/

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gzt

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# 1768801 22-Apr-2017 11:58

Is that gas fired or electric?

gzt

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# 1768804 22-Apr-2017 12:01

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Jase2985:
how is the tank heated?, how warm is the tank to touch?

the time it takes for the shower to get warm will be due to the length of pipe and the need to heat it more so than the tank being uninsulated. as the tank should always be the correct temperature (unless you have just used a lot of water, then it will be reheating that)

Agree.Lagging the pipes is essential in this scenario and will be the main factor in being very slow to deliver hot water to the tap. There is an excellent neoprene product designed for this. It is half cut and slips over the pipes laterally.

richms

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# 1768837 22-Apr-2017 12:37

Also thinner pipes helps a lot with getting water faster as there is less cold in them to displace.

Richard rich.ms

Hammerer

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# 1768839 22-Apr-2017 12:39

Adding a cylinder wrap to hot water cylinders has a very good economic return even on the latest cylinders. But most sites say that you should not put a cylinder wrap on a gas hot water cylinder:

https://www.energywise.govt.nz/at-home/water/saving-money-on-hot-water/

Wrap your hot water cylinder and hot water pipe

Pre-2002 electric hot water cylinders aren't insulated very well and should have a cylinder wrap. You should also insulate the first 1-1.5 m of hot water pipe coming off your hot water cylinder. Cylinder wraps cost around $60 and pipe insulation is about $5 a metre from hardware stores. For an older (pre-1987) cylinder and pipes, you could save about $80 a year. Note that you can't put a cylinder wrap on a gas hot water system.

http://www.smarterhomes.org.nz/energy/water-heating/

Heat loss from gas hot water cylinders is large but it’s not safe to put a hot water cylinder wrap on a gas cylinder.

...

If you have an older cylinder, which is not as well insulated, then adding a cylinder wrap could save you up to 1 kWh/day (saving about $93 per year at 25.5 cents/kWh). Wraps cost very little – about $70 in 2012 – so insulating your cylinder could pay for itself in less than a year.

Apparently, the current safety requirements may be more stringent than when I looked at getting a gas hot water cylinder more than a decade ago:

http://www.level.org.nz/water/water-supply/hot-water-supply/storage-cylinders/

Specific requirements for gas storage water heaters

Gas storage water heaters must have:

adequate ventilation of the cylinder
a flue to remove exhaust gases.
They must be:

serviced annually
flushed out regularly to remove water sediment at the bottom of the cylinder
checked to ensure that vents are not blocked.

Shindig

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# 1768888 22-Apr-2017 14:09

It is gas fired, when i re-looked I can see the flue.

I assume with it being gas, this is why it isnt insulated. There must be something I can do?

Good point on the pipes, I will get some insulation for those. ]

cheers for the replies.

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Jase2985

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# 1768942 22-Apr-2017 15:29

unless you can find an insulation material suitable for insulating a gas cylinder not much you can do. but thats not why its taking your shower longer to get hot.

the lack of insulation on the cylinder is just causing you to have to use more energy to keep it warm.

cadman

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# 1768946 22-Apr-2017 15:55

It is insulated - with a cladding over the insulation.

In mild climates such as ours lagging pipes is not beneficial where they're not in use for long periods.

Hammerer

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# 1768989 22-Apr-2017 17:41

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cadman:

In mild climates such as ours lagging pipes is not beneficial where they're not in use for long periods.

Insulating hot water pipes is always beneficial so I presume that you mean there may not be a positive financial return.

But even in the scenario "where they're not in use for long periods" - where the standing water in the pipes has time to cool down close to the environmental temperature - that does not mean there is no positive financial return. You would have to know the usage profile, the water temperatures, the pipe characterstics (length, diameter, material) and environmental factors (temperature, underground, in concrete, and so on).

In the absence of sufficient detail, the more sensible decision is to insulate the pipes. This is also recommended by BRANZ and the building code, even for hot water vent pipes.

gzt

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# 1769007 22-Apr-2017 19:34

Shindig:
It is gas fired, when i re-looked I can see the flue.

I assume with it being gas, this is why it isnt insulated. There must be something I can do?

I'm not sure. Maybe you could insulate the enclosure on the outside. There is an insulation product made for motorhomes can't remember the name. It is R6.1 and in sheet form. Usually blue. I made a chilly bin out of it that lasted a week in hot summer.

On the other hand, It is a gas installation. It is subject to various regulations and good practices for good reasons. It could be that your existing enclosure is not compliant and never has been. The best solution for gas economy, utility, and safety might be a total replacement of the w heater.

Tldr; understand gas regulations and practices to ensure you are not making a bad situation worse before starting.

Aredwood

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# 1769009 22-Apr-2017 19:44

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You might have a stuffed tempering valve. As I can see that it is installed really close to the cylinder, Which is never good for them As the heat from the cylinder means that the valve stays hot 24/7 Therefore they corrode faster and minerals tend to buildup inside them. Although it doesn't say so in the plumbing codes, they last the longest when they are installed so the valve completely cools down when no hot water is getting used.

And since the cylinder is a Ruud cylinder, The dip tubes often fail on them. Meaning the incoming cold water mixes with the hot. Instead of the cold water being delivered to the bottom of the cylinder. Although usual symptom of this is water hot at first, then looses temp to only warmish water.

As for pipe insulation, best bang for buck is to only insulate the pipes near the cylinder connections that stay warm all the time.

[edited to add]

Don't bother insulating the outside of an internal gas hot water cylinder. As the major heat loss from them is via the flue. And the safety reason why you don't insulate a gas cylinder is they almost always have air intakes near the bottom and by the flue connection. If you block them it causes major combustion problems. They also need to be installed behind a fume barrier if installed in a garage. Due to the risk of petrol vapours catching on fire.

Efficiency wise those cylinders are poor compared to infinity continuous flow heaters or modern storage outdoor gas heaters like the Rheem Stellar. And due to their cost it would be very rare for one to be installed as a new installation anyway. But assuming it is using Natural gas, it will still be cheaper to operate than an electric cylinder. As natural gas is so cheap.

gzt

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# 1769015 22-Apr-2017 19:48

Aredwood, Is the current enclosure legal and compliant?

Aredwood

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# 1769022 22-Apr-2017 20:12

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gzt: Aredwood, Is the current enclosure legal and compliant?

Nothing majorly wrong. Of course the panel by the burner should be removable for servicing access. And since that particular model of heater is balanced flue. It doesn't need ventilation openings for air to the burner. And Im guessing it is open at the top due to the camera angle. And guessing that the floor is concrete. Earthquake straps are not compliant though. But not worth worrying about them on an old cylinder. Probably some other minor non compliance matters to do with the installation as well. But doesn't appear to be anything in the "major hazard" category. Although assessing the safety would also mean checking the flue terminal location and checking some other things that you cant do with just a photo.

Main thing is what room is the cylinder is installed in? Is it in a garage?

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